Establishment of compatibility in the Ustilago maydis/maize pathosystem

The fungus Ustilago maydis is a biotrophic pathogen parasitizing on maize. The most prominent symptoms of the disease are large tumors in which fungal proliferation and spore differentiation occur. In this study, we have analyzed early and late tumor stages by confocal microscopy. We show that fungal differentiation occurs both within plant cells as well as in cavities where huge aggregates of fungal mycelium develop. U. maydis is poorly equipped with plant CWDEs and we demonstrate by array analysis that the respective genes follow distinct expression profiles at early and late stages of tumor development. For the set of three genes coding for pectinolytic enzymes, deletion mutants were generated by gene replacement. Neither single nor triple mutants were affected in pathogenic development. Based on our studies, we consider it unlikely that U. maydis feeds on carbohydrates derived from the digestion of plant cell wall material, but uses its set of plant CWDEs for softening the cell wall structure as a prerequisite for in planta growth.     

Clock controls timing of mouse pancreatic differentiation through regulation of Wnt- and Notch-based and cell division components

The oscillations of circadian genes control the daily circadian clock, regulating a diverse array of physiologies with the 24-hour light/dark cue across a wide variety of organisms. Here we first show that before embryonic circadian rhythms occur, the oscillation (nucleocytoplasmic shuttling) of core circadian gene Clock is tissue-specific and correlated with the state of differentiation during both early development and later pancreas organogenesis. Disruption of Clock as well as Timeless in the embryonic pancreas does not block pancreatic differentiation but alters the balance and maturity of endocrine and exocrine cells. Molecular analysis indicates that inhibition of Clock or Timeless expression disturbs not only cell cycle regulators, but also Wnt- and Notch-signaling components, whose oscillations establish the timing mechanism in somitogenesis. Thus, our results provide new insights about circadian genes' function in control of the timing of differentiation during embryonic development.     

Developability studies before initiation of process development

Monoclonal antibodies constitute a robust class of therapeutic proteins. Their stability, resistance to stress conditions and high solubility have allowed the successful development and commercialization of over 40 antibody-based drugs. Although mAbs enjoy a relatively high probability of success compared with other therapeutic proteins, examples of projects that are suspended due to the instability of the molecule are not uncommon. Developability assessment studies have therefore been devised to identify early during process development problems associated with stability, solubility that is insufficient to meet expected dosing or sensitivity to stress. This set of experiments includes short-term stability studies at 2−8 þC, 25 þC and 40 þC, freeze-thaw studies, limited forced degradation studies and determination of the viscosity of high concentration samples. We present here three case studies reflecting three typical outcomes: (1) no major or unexpected degradation is found and the study results are used to inform early identification of degradation pathways and potential critical quality attributes within the Quality by Design framework defined by US Food and Drug Administration guidance documents; (2) identification of specific degradation pathway(s) that do not affect potency of the molecule, with subsequent definition of proper process control and formulation strategies; and (3) identification of degradation that affects potency, resulting in program termination and reallocation of resources.     

中华通草蛉成虫越冬体色变化与滞育的关系

对自然条件下中华通草蛉成虫越冬体色变化与滞育关系的系统研究表明,成虫在越冬过程中都经历了一个较明显的体色变化过程,主要表现在体躯底色从绿色到土黄色及体背面滞育斑由褐色到红褐色的改变,据此将成虫体色分成5个级别,在越冬过程中约80%个体体色经历了在生殖型体色（1级）和滞育型体色（4,5级）之间的明显变化,约有20%个体体色维持在2、3级,在越冬前,成虫滞育斑出现后其卵巢不再发育或者发育受抑而逐渐停止发育,滞育斑的出现是成虫开始滞育的重要标志;越冬后,随着成虫体色由滞育型向生殖型的转变,当大多数个体体色变为3级以下时,卵巢开始发育,这些结果说明,中华通草蛉越冬成虫体色的变化是其滞育越冬的一个重要形态指标,越冬前后体色的改变,标志着成虫滞育的开始和结束。     

Making heads from tails: Development of a reversed anterior-posterior axis during budding in an acoel

The anterior-posterior axis is a key feature of the bilaterian body plan. Although axis specification during embryogenesis has been studied extensively, virtually nothing is known about how this axis can be established post-embryonically, as occurs in budding animals. We investigated bud formation in the acoel Convolutriloba retrogemma, which reproduces by a remarkable process involving the formation of animals with linked but completely opposite body axes. Reverse axes are established anew during each round of budding and manifestations of the bud's new axis develop gradually, with regionalization of axial patterning genes (Hox and otx) and the establishment of organized musculature occurring secondarily, after bud initiation. A swath of tissue at the parent-bud boundary has no regenerative potential and appears devoid of inherent axial polarity. GSK-3 inhibitor trials suggest that Wnt/β-catenin or Hedgehog signalling may mediate the establishment of this unpolarized zone. Formation of unpolarized tissue may provide a buffer between opposing polarity cues and be a general mechanism by which budding animals establish and maintain linked body axes. In addition to elucidating the developmental basis of budding in a bilaterian, this study provides insight into convergence in animal budding mechanisms, redeployment of embryonic gene expression during budding, and Hox gene evolution.     

DNA damage in the early primordial anther is closely correlated with stamen arrest in the female flower of cucumber (<Emphasis Type="Italic">Cucumis sativus</Emphasis> L.)

To investigate the regulatory mechanisms of sex expression in cucumber, morphological observations and biochemical analyses were carried out on inappropriate stamen development of female flowers of cucumber. It was found that developmental arrest of the inappropriate stamen mainly occurs at the anther primordium. This arrest is closely correlated with DNA damage, as detected by TUNEL assay, and might result from anther-specific DNase activation. It was also found that the DNA damage does not lead to cell degeneration, although chromatin condensation is observed in the anther primordia.Abbreviations DAPI 4,6-diamidine-2-phenylindole dihydrochloride - MTT 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide - PCD programmed cell death - TUNEL TdT-mediated dUTP nick-end labeling     

Developmental toxicity studies of lumefantrine and artemether in rats and rabbits

The combination of artemether plus lumefantrine is a type of artemisinin‐based combination therapy (ACT) recommended by the World Health Organization for uncomplicated falciparum malaria except in the first trimester of pregnancy. The first trimester restriction was based on the marked embryotoxicity in animals (including embryo death and cardiac and skeletal malformations) of artemisinins such as artesunate, dihydroartemisinin, and artemether. Before recommending ACTs for use in the first trimester, the World Health Organization has requested that all information relevant to the assessment of risk of ACTs to the embryo be made available to the public. This report describes the results of embryo‐fetal development studies of artemether alone, lumefantrine alone, and the combination in rats and rabbits as well as toxicokinetic studies of lumefantrine in pregnant rabbits. The developmental no‐effect levels for lumefantrine were 300 mg/kg/day in rats (based on a 25% decrease in litter size at 1000 mg/kg/day) and 1000 mg/kg/day in rabbits. The calculated safety margins based on human equivalent dose and plasma C_max and AUC values were in the range of 2.5‐ to 17‐fold. The developmental no‐effect levels for artemether were 3 mg/kg/day in rats and 25 mg/kg/day in rabbits. Lumefantrine caused no teratogenicity and was not a potent embryotoxin in rats and rabbits. Expected artemisinin‐like findings were seen with artemether alone and with artemether/lumefantrine combined except that no malformations were observed. There were no findings in pregnant rats and rabbits that would cause increased concern for the use of artemether–lumefantrine in the first trimester compared to other ACTs.